The present invention relates to the art of snowplows for automotive vehicles and controls therefor and, more particularly, to the manually operable control device located in the cab of the vehicle and by which the position of the plow blade is controlled.
The present invention finds particular utility in conjunction with a snowplow and control system of the character disclosed in U.S. Pat. No. 3,706,144 to Miceli which is owned by the assignee of the present invention and the disclosure of which is hereby incorporated herein by reference. Accordingly, the invention will be disclosed and described in detail herein in conjunction with a plow and control system according to the latter patent. At the same time, however, it will be appreciated that the invention is applicable to other snowplow and control system arrangements.
In a snowplow and control system arrangement of the character disclosed in the Miceli patent, the snowplow blade is mounted on the front of a car, small truck, or the like, together with hydraulic cylinders by which the blade is elevated and lowered relative to the vehicle and the underlying ground and by which the blade is angled to the left or right relative to the vehicle and ground. The plow and control system further includes solenoid operated valves by which the flow of hydraulic fluid to and from the cylinders is controlled to achieve the various positioning functions. Selective positioning of the plow blade through control of the solenoid valves and an electric motor driven hydraulic pump in the system is achieved through a control device mounted in the cab of the vehicle such as on the dashboard thereof for operation by the vehicle operator, whereby only an electrical cord of sheathed conductors extends from the cab of the vehicle to the operating components of the system. In the Miceli patent, the control device includes a pair of pivotal operating switch levers which serve to control the electrical system and, in turn, the hydraulic system of the plow. Each lever has a neutral or hold position to which the lever has to be manually returned, and one of the levers is pivotal relative to the hold position to selectively achieve raising and lowering of the blade while the other lever is pivotal from its hold position to selectively achieve left or right angling of the blade.
Heretofore, the control device has been mounted in the cab of the vehicle in a location fixed relative thereto, generally at the time of installation of the system. When mounted, the electrical cord leading from the device to the solenoid valves and pump extends under the dashboard of the vehicle and through the fire wall. The control device is generally mounted on the dashboard so as to minimize the length of cord exposed in the cab. However, the control device is often permanently mounted on a console of the vehicle between the front seats, whereby the cord runs across the floor of the vehicle to the fire wall.
Permanent mounting of the control device either on the dashboard or console minimizes or undesirably limits convenience and efficiency with respect to the vehicle operator's control of both the vehicle and the snowplow during a snowplowing operation. In this respect, it will be appreciated that the vehicle operator must steer the vehicle with one hand and manipulate the components on the control device with the other to adjust the position of the plow blade during a snowplowing operation. Depending on the make of the vehicle and the physical size of the operator, dashboard mounting may require the operator to lean forward in the driver's seat to manipulate the control device components, and such body motion or movement can detract from the operator's efficiency in controlling steering of the vehicle and manipulation of the floor pedals. Moreover, a given snowplow vehicle may be driven by several operators each having different physical characteristics, and this too can lead to inconvenience and discomfort for the operator in driving the vehicle and manipulating the snowplow control components during a snowplowing operation. For example, if the control device is mounted on the dashboard to the right of the steering wheel of the vehicle, or on the console, and the vehicle operator is left handed, and not particularly ambidextrous, manipulation of the control device components with the operator's right hand may be awkward as well as difficult for the operator. It will be appreciated, therefore, that the mounting of the control device in a fixed location on the dashboard, console or elsewhere in the vehicle cab area is extremely limiting with respect to convenience of the operator and, in turn, the latter's efficiency in operating the vehicle and snowplow. This can lead to operator fatigue and, more importantly, the potential danger of operating the vehicle with less than a desirable degree of control thereof.
Yet another problem exists with respect to the potential inadvertent and unintended displacement of the snowplow blade during non-snowplow operation of the vehicle in, for example, moving from one snowplow operating location to another. More particularly in this respect, the control device is connected to the vehicle battery through the vehicle ignition system, whereby the control device and thus the electrical components in the system are in an operable mode whenever the vehicle ignition switch is turned on. Thus, for example, if the snowplow is in an elevated position and the vehicle is being driven in a non-snowplowing operation, unintentional or accidental contact with a control component on the control device can result in undesirable movement of the plow blade relative to the vehicle and the underlying roadway. The potential for damaging the snowplow unit and/or the vehicle and/or injuring the vehicle operator will be appreciated simply by imagining what would happen if the plow blade was lowered to engage the underlying roadway while the vehicle was being operated at a high rate of speed, such lowering being possible by inadvertent actuation of the down component on the control device.